1. Field of the Invention
The present invention relates to a gas suction pump device, a gas feed adapter and a gas alarm unit.
2. Description of the Background Art
There are generally frequent occasions when it may be possible in, for example, underground job sites or gateways, or other places where persons enter, or working regions that air in an environmental atmosphere is in a dangerous state, or will become a dangerous state, such as occasions when harmful gases such as carbon monoxide and hydrogen sulfide gases may possibly be contained in air in such an environment, or when the oxygen gas concentration in air may possibly be lowered.
When the air in the environmental atmosphere has become a dangerous state to persons due to high concentration of the dangerous gases contained or low oxygen gas concentration, it is necessary to sense the fact.
From such a demand, there have been proposed various types of portable gas alarm devices to date. As such portable gas alarm devices, for example, those having a structure that a sucking means such as a pump is installed in a gas alarm device body, and air in the objective space is forcedly sucked by this sucking means to perform the concentration measurement of a gas to be detected, and those of the so-called xe2x80x9cdiffusion typexe2x80x9d that air in the objective space is introduced by natural diffusion are known.
However, such a portable gas alarm device cannot be used in a place where no person can enter because the portable gas alarm device basically requires that a person should enter the place to perform the concentration measurement of dangerous gases in order to confirm the safety of air in an environmental atmosphere.
Therefore a method is used in which a sucking device such as a pump is connected to the portable gas alarm device so as to suck air in the objective space to perform the concentration measurement of the dangerous gases up to the gas alarm device body by the sucking device.
Since the conventional sucking devices are generally large in size and heavy, however, they involve problems that they are considerably unhandy to carry and make a great obstacle to practice the intended work or the like.
In addition at the actual situation, such a sucking device is unsuitable for use as a sucking means that is connected to the portable gas alarm device, because it requires much time or labor in maintenance work such as filter exchange or pump exchange.
The present invention has been made on the basis of the foregoing circumstances.
It is the first object of the present invention to provide a gas suction pump device which is easy to be fabricated as a small-sized one handy to carry and high in convenience for use.
The second object of the present invention is to provide a gas feed adapter by which air from such a gas suction pump device can be surely fed to a gas detecting part of a portable gas alarm device.
The third object of the present invention is to provide a portable gas alarm unit which makes good use of such a gas suction pump device and is high in convenience for use.
The first object of the present invention can be achieved by any one of the following constitutions [1] to [8].
[1] A gas suction pump device suitable for being connected by a connecting tube to a portable gas alarm device for use, which comprises:
a casing having a substantially rectangular frame-like sectional shape composed of 2 side walls opposite to each other, and upper and lower walls which connect the side walls to each other, and formed slenderly in a gas flowing direction and into a size holdable by grasping with a hand;
a control circuit board provided in the casing so as to extend in a longitudinal direction along the upper wall;
a pump unit arranged in a region on the side of one side wall under the control circuit board, in which one end and the other end of a gas flow path defined by the pump unit and extending in the longitudinal direction of the casing communicate with a gas inlet port opened forward of the casing and a gas outlet port opened backward of the casing, respectively; and
a battery fitting chamber provided in a region on the side of the other side wall.
[2] The gas suction pump device according to the constitution [1], wherein the pump unit is composed of a pump and a pump driving motor provided integrally with the pump, and wherein
the pump is located in the vicinity of one side wall in the casing, and the pump driving motor is arranged in a state located in the vicinity of the other side wall.
[3] The gas suction pump device according to the constitution [2], wherein the pump making up the pump unit has a gas discharge quantity of 0.2 to 0.5 L/min.
[4] The gas suction pump device according to any one of the constitutions [1] to [3], wherein a driving power source is a battery.
[5] The gas suction pump device according to any one of the constitutions [1] to [4], wherein a recessed part for receiving an end part of the connecting tube is formed in the casing, and a connecting terminal to which the connecting tube is connected is provided at the gas outlet port in the recessed part in a state projected backward from the rear wall thereof.
[6] The gas suction pump device according to any one of the constitutions [1] to [5], wherein a branched gas flow path opened upward is defined in a gas flow path forming member connecting the pump unit to the gas outlet port, and a pressure sensor is connected to the branched gas flow path in a state arranged on the control circuit board side of the gas flow path forming member.
[7] The gas suction pump device according to any one of the constitutions [1] to [6], wherein the casing is formed by joining a front case with a rear case detachably to each other, and an anti-detaching metal band for preventing both front case and rear case from detaching from each other is fitted on the joined area between the front case and the rear case.
[8] The gas suction pump device according to the constitution [7], wherein the anti-detaching preventing metal band is fitted in a state that both ends thereof overlap each other and fixed to the casing by a screw at a position where both ends overlap each other.
The second object of the present invention can be achieved by the following constitution [9].
[9] A gas feed adapter for connecting the gas suction pump device according to any one of the constitutions [1] to [8] through a connecting tube to a portable gas alarm device equipped with a plurality of gas sensors which detect gases of different kinds from one another, which comprises:
a casing having an engaging part and detachably engaged with a gas alarm device body, wherein a gas feed port common to the respective gas sensors in the gas alarm device body is defined in one outer end wall of the casing, a connecting terminal to which the connecting tube is connected is also fitted so as to project outward, and a gas outlet for opening the internal space in the casing to the air is defined in the other outer end wall, and wherein
a main gas inlet passage extending zigzag from one to the other in the casing is formed in the casing, and a plurality of branched gas inlet passages independent of one another for introducing air in the objective space to perform the measurement of gases into the respective gas sensors in the gas alarm device body are formed in the main gas inlet passage.
The third object of the present invention can be achieved by any one of the following constitutions [10] to [14].
[10] A gas alarm unit comprising the gas suction pump device according to any one of above the constructions [1] to [8], a connecting tube connected to the gas suction pump device at an end thereof and a portable gas alarm device connected to the other end of the connecting tube through the gas feed adapter according to the construction [9], into which air in the objective space to perform the measurement of gases is introduced from the gas suction pump device.
[11] The gas alarm unit according to the construction [10], wherein the portable gas alarm device comprises a substantially box-like casing composed of a case body provided with a fitting member fixing part in which a fitting member for fitting on a person""s body to carry the alarm device is installed and having an opening at a lower part, and a lid for closing the opening in the case body, and a gas detecting part is formed at one side surface of the casing in such a manner that a plurality of the gas sensors are arranged side by side in a plane direction of said one side surface.
[12] The gas alarm unit according to the construction [11], wherein a power unit composed of a circuit board flat in shape, on which a secondary battery as a driving power source, a charging terminal for charging the secondary battery and a current limiting resistance are mounted, and an insulating cover provided so as to cover the secondary battery and the current limiting resistance on the circuit board is provided in the casing in such a manner that the circuit board extends in parallel with the lid in the casing, and wherein
an alarm annunciating mechanism that raises an alarm when the concentration of a gas detected by the gas sensor exceeds a reference value preset about the gas, and a display mechanism for displaying the concentration of the gas detected by the gas sensor are arranged so as to stand in a plane direction of the circuit board in a state that the alarm annunciating mechanism is located over the secondary battery in the power unit.
[13] The gas alarm unit according to the construction [11] or [12], wherein a plurality of the gas sensors are fixed and held by a gas sensor fixing frame member, in which gas inlet ports for the respective gas sensors have been formed in a state independent of one another, in the gas detecting part.
[14] The gas alarm unit according to any one of the constructions [11] to [13], wherein 4 gas sensors are arranged in the gas detecting part, and the objective gases to be detected by the gas sensors are gases of oxygen, hydrogen sulfide, carbon monoxide and hydrocarbon.
According to the gas suction pump device of the above-described construction, the casing is in the form holdable by grasping by a hand, and the constituent members of the pump device are rationally arranged in a state that a dead space in the casing becomes as small as possible, whereby the gas suction pump device itself can be provided as a small-sized and light-weight one while retaining basically necessary functions. Accordingly, the gas suction pump devices are excellent in portability, and so actually high in convenience can be achieved.
According to the gas feed adapter of the above-described constitution, a state substantially equal to natural diffusion can be realized as the main gas inlet passage for feeding air in the objective space to perform gas measurement to a gas alarm device is opened to the atmosphere or air though the air is forcedly introduced by a gas suction pump device. In addition, the main gas inlet passage is formed so as to extend zigzag, and the branched gas inlet passages are formed corresponding to the respective gas sensors, whereby air introduced by the gas suction pump device can be surely fed to the respective gas sensors.
According to the portable gas alarm units of the above-described constructions, the portable gas alarm device is fitted to the body of a person and carried together with the body by the person because the pump device making up the gas alarm unit has high convenience while retaining the necessary functions, and moreover the pump device can be held for use by grasping it by a hand, whereby the gas alarm unit has extremely high convenience for use as a portable gas alarm unit. Accordingly, concentration measurement of dangerous gases can be performed even in a place where no person can enter, and high safety can be achieved.